Double-acting saw.



(No Modal.)

G. B. PEART.

DOUBLE ACTING SAW.-

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Pgtonted Aug. 5, I902.

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UNITED STATES [PATENT OFFICE.

GEORGE RICHARD PEART, OF SHEFFIELD, ENGLAND, ASSIGNOR OF ONE- HALF-TO FRANK FOXON, OF SHEFFIELD ENGLAND.

DOUBLE-ACTING SAW.

SPECIFICATION formingpart of Letters Patent No. 706,447, dated August 5, 1902-. A lication filed September 9, 1901. Serial No. 74,816. (No model.)

To aZZ whom it may concern.-

Be it known that I, GEORGE RICHARD PEART, a subject of the King of Great Brit ain, and a resident at the Union Saw Mills, Charles street, Sheflield, county of York, England, have invented a certain new and useful Improvementin Double-Acting Saws, (for which I have applied for a patent in Great Britain,No. 8,737, bearing date Apri129, 1901,) of which the following is a specification.

The objects of my invention are to avoid clogging the saw-gate with sawdust, to facilitate the resharpening, and to enable such saws to be retoothed by an ordinary millhand instead of sending them to a manufacturer or an expert. The resulting advantages are a prolonged working life of the saw, nonheating of the saw, and less power required to drive it.

Referring to the drawings which form 'a part of this specification, Figure 1 represents a piece of a mill-saw with the teeth arranged according to my invent-ion; Fig. 2, the same when partly worn down; Fig. ,3,- the same when ready to be retoothed.

My invention is applicable to all saws having a double or reciprocating action and required to cut in both directions-such, for example, as millwebs, gang-saws, crosscutsaws, and the like-and it refers more particularly to the arrangement of the teeth of such saws. I,

Although I have only shown one form of tooth in the drawings, it must be understood that I do not confine my invention to that particular form.

In carrying my invention into practice, as shown in the drawings, I arrangethe teeth in pairs, which I have marked A, B, and O. The two teeth which constitute a pair face in bpposite directions, but are set to thesame side of the saw-blade. Thus the tooth marked 1 faces to the left hand and cuts when the saw moves in the proper direction; the same with 3 and 5 of the other pairs B and C. The next pair of teeth (marked B) are facsimiles of the first-named pair; but they are both set to the opposite side of the saw-blade, and the pair marked 0 are again reversed in setting to the same side as those of A. Thus each adjacent pair of teeth,with their backs to each other, are set alternately in opposite directions, and this apparently small deviation from the usual practice of construction pro duces in practice very beneficial results both in the working life of the saw and in a superior finish of cut surface.

When the continual sharpening of the teeth reduces the width of the saw-blade:say, for

example, from four and a half inches to three inches-the teeth and spaces or gullets assume the appearance shown in Fig. 2. The gullets a, b, and c are ground in new proportionst'. 6., narrower-while the gullets d and e are ground in new proportions- 6. e. ,Widerfrom the action of the emery-wheel upon the vertical faces of the teeth 2 and 3 and 4 and 5, as seen in Fig. 2. This grinding or regulleting in new proportions is due to the fact that in order tokeep the points ofthe teeth in the gullets cl'squared up or sharp it is necessary to grind away the vertical faces, this resulting inwidening the gullets. Now if the gul lets a. were reground of the same width as fore reground narrower.

When the teeth and gullets assume the con figuration shown in Fig. 3, the saw requires retoothing, and this is mosteconomically per= formed bycutting ofi the tops of the teeth in the manner indicated by the dotted lines in Fig. 3. This operation causes the teeth 2 and 3 to become a pair, and 4: and 5 also become a pair and are set in the manner before de scribed. By this arrangement of topping the teeth the loss in the Width of the saw is not more than one-eighth of an inch.

Having now described my invention, what Iclairn as new, and desire. to secure by Letters Patent, is, I

A saw having its teeth arranged in pairs, 1 and 2, 3 and 4: and so on, with gullets a, 1), between the members of each pair and with the gullets cl, 6, separating one pair of teeth from the next, the teeth of each pair having their edges converging inwardly toward the bottom of the gullet between them being sharpened from the same side and both set over in the same direction.

In Witness whereof I have hereunto set my hand in presence of two witnesses.

GEORGE RICHARD PEART.

Witnesses:

RoBnF. DRURY, E. DIXIE DRURY. 

